rockspecs: lua-stdlib 35 was renamed back to stdlib in LR repo.

* rockspec.conf (dependencies): Rename lua-stdlib back to stdlib
to match LuaRocks repo renaming.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
configury: don't generate zmacs.1 before zmacs itself is ready.

* lib/zmacs/zmacs.mk (doc/zmacs.1): Depend on dist_zmacsdata_DATA
to make sure all zmacs sources are available before running
help2man.
(zmacs_zmacs_DEPS): Remove unused nodist_zmacsdata_DATA reference.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
zlisp: t and nil are special forms, not variable references.

* lib/zmacs/eval.lua (evalexpr): Intercept nil and t expressions
before trying to find their valuas.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>